I'm gonna go ahead and toss in my 2 cents as well... if you want all-around versatility, choosing the shorter rod is going to limit your capabilities. I'd go with the longest rod I could get my hands on. I'm fishing an 8'4" TLS Power Matrix 3 wt these days more than my TFO 8'6" 4 wt, and I can tell you that I wish my TLS was longer!

BTW, if you ask Jim Casada what he'd pick, he'd lean towards the longer rod, and you won't find many folks alive that have fished more in the Park.

One last note... go with your instincts. If you know what you're doing, you can catch trout all day in the Park on a 6' cane pole. Get the rod you'll be most satisfied with.

I use a 9' helios and 8'6" TFO rod in the park. I like the 9' better. It helps me keep my line off the water better especially when I try to keep it over swift water to get to the pool I want to fish. So I would say get the 8'4".

Jason--I'm a staunch proponent of longer rods. Get the 8'4" (and the 4-weight is a fine choice). Also, there was considerable interchange on this subject a few weeks back. You might want to do some looking at the various opinions as well as the rationale which underlay them. A bunch of folks had sound points.
Jim Casadawww.jimcasadaoutdoors.com

Hey Jim I remember seeing an old picture of Mark Cathey in your book holding a fly rod. I thought it looked like a pretty long 9' rod am I mistaken? Just trying to get some perspective on what old timers like Mr. Cathey used when fishing in the smokies.

Thanks again guys for all the fine suggestions.Jim I look forward to reading your book on the Smokies. Jeffnles1 I've been reading your blog and your G2 pic was my inspiration to get one.I do prefer a lighter action.